Just like in many countries, in Turkey, Northern Bluefin Tuna (NBTs) are considered to be high profitable fish species. NBTs, which are the members of Scombridae family, are of an average 120–250 cm fork–tailed length and weight 26–250 kg. NBTs have been grown in cages and exported from Turkey to far East Countries, since 2002.
In this case, it leads to increase the fishing of NBT, therefore wild NBT population stock is under the threat of overfishing in Turkey. Furthermore, there is not enough research on high stocking stress effects on NBTs and he flesh quality of the fish.
In this study, the antioxidant enzymes; [superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat)], lipid peroxidation (LPO), glutathione (GSH) and cortisol levels, which have taken from blood samples of captive and wild NBT, have been investigated. All the data is grouped according to weight, sex and age. The student's t test, the one-way ANOVA and the statistical confidence tests (p<0.05 and p<0.001) have been applied to the results of the study.
According to results, a high activity of antioxidant enzymes, LPO, cortisol have been found in the blood of the captive NBT samples, but the GSH levels of blood have turned out to be low in comparison to the wild NBT samples. These two findings show that captive NBTs suffer from stress more than wild NBTs.
